1. Field of the Invention
The present invention relates to a defrost control apparatus for refrigerator. More specifically, the defroster which defrosts a condenser by supplying a high-temperature refrigerant by means of switching of a refrigerant flow switching valve in a refrigeration cycle or by heating an electric heater.
2. Description of the Prior Art
A conventional defrost control apparatus for refrigerator is disclosed in, for example, Japanese Utility Model Publication No. 55-7795 published on Feb. 21, 1980. In the prior art, operating hours of a refrigeration cycle is integrated by a timer, and a defrost operation is started at every time point that the integrated hours reaches a predetermined time.
However, in such a prior art, since the defrost operation is started at arbitrary time points by the timer, there was a problem that a temperature of a storage room is increased because it is impossible to refrigerate the storage room when the defrost operation is performed. That is, in a case where the defrost operation is started in a time zone wherein a frequency of opening/closing of the door of the storage room is large, in spite of a state where the storage room cannot be refrigerated, the outside air frequently enters in the storage room.